Hacker News new | past | comments | ask | show | jobs | submit login
Ask HN: Is FaceID harmfull for your eyes?
54 points by sfilargi on Oct 29, 2018 | hide | past | web | favorite | 32 comments
No, this is not a flamebait, hear me out.

Since I got the iPhone X I have noticed that when I would watch movies in bed at night, I would wake up with sore eyes that would eventually turn into headaches.

Searching the web I found a lot of people complaining about the PWM on the iPhone X, and I got convinced that it was the screen that was causing my eye strain, so stopped using the X.

Until I got the XR a few days ago. As usual I watched some Netflix while in bed before falling asleep and woke up with the all so familiar sore eyes. This meant that all this time it was not the OLED the one responsible for my headaches, but something else. The only other think that was new both in X and XR was the FaceID.

I started thinking how can it cause problems and came with the theory below. When I am at bed the room is really dark and so I set the brightness level on my iPhone to the lowest setting. My eye-pupils are fully dilated to adjust to the lack of light. My theory is that the FaceID illuminator doesn't take into consideration the amount of light in the environment and uses the same intensity as if it was daylight.

To prove this I took a recording of my iPhone X in similar environment with an IR camera: https://youtu.be/7ewR9wUjnsc

If this wasn't IR but visible light it would be like the iPhone's camera flash going on every 5 seconds right in front of my eyes. There is no question that this would justify the morning soreness and headaches.

My question is: Does the IR light emitted by the iPhone "flood illuminator" have the same effect to my retina even thought I don't perceive it?

"If this wasn't IR but visible light it would be like the iPhone's camera flash going on every 5 seconds right in front of my eyes. There is no question that this would justify the morning soreness and headaches."

Yeah, but that's because your eyelids would be twitching and your temporal muscles contracting in response to to flash. When it's IR you can't see it so your body doesn't do anything in response.

IR light is, in general, very low-energy. Individual photons don't carry enough energy to disturb chemical bonds. The "flash" you're seeing there is less bright than a candle. The flickering not bright at all it's just that CCDs are very good at picking IR light up.

No part of your body can sense or respond to this and even if they did it wouldn't cause soreness.

The IR "flash" you filmed with your phone is about as bright as a television remote control. It's literally impossible that this is causing headaches.

Your headaches come from looking at an illuminated object in a darkish room that's only a few feet from your eyes. Screens in the dark cause eyestrain.

The darker an environment is the more open your pupil is. This reduces the pin-hole focusing effect of the pupil and requires that the lens of the eye be more carefully focused to see. Focusing that tightly is difficult because the lens muscles have to stay in one level of contraction for a long time.

Your body instinctively tries to squint so that the eyelids being close together and the eyelashes will cause a pinhole effect that will help you see. The fight between squinting for focus and opening your eyelids to make things less dark makes your head sore and causes tension headaches. This effect becomes more pronounced with age.

The first thing you said about PWM? That's a thing people say when they're not doing so well with cause and effect and cognitive bias. This new thing you're inventing about the IR is a much worse version of that.

It doesn't have a damn thing to do with the manufacture or components of your phone. Stop trying to read a phone screen (or look at anything on a phone close up) in a dark room. That's it. Don't do that. It's a thing that makes your eyes and head sore. It's really well documented. No new explanation is needed.

Your post makes sense.

What doesn't make sense to me, and drove me down this rabbit hole, is that I do the same things with the X that I used to do with the 3GS, 4, 6, 7+ and 8+. Never had a single problem.

> Stop trying to read a phone screen (or look at anything on a phone close up) in a dark room. That's it. Don't do that. It's a thing that makes your eyes and head sore. It's really well documented.

True, true. But it doesn't mean that if you sore eyes it's always because of that.

Do you ever have the feeling of wanting to know what causes something. Not to prove something, not for any other reason other than figure out why and how. I am in that rabbit hole. I am very happy with the 8+ and have no eye problems at all. But I have to known what is it in X that causes my eyes to go sore.

The simplest answer is that you're starting to have the very slightest amount of age-related focus degradation, that it's only manifesting when the room is very dark, and that it aligned with the new phones by coincidence.

That said, older phones had a higher minimum brightness and more mixed-in blue light. Your pupils will contract more when looking at a brighter, bluer screen and smaller pupils focus more easily. Also, being able to see the black part of the screen can make it easier to focus because you can see how far away it is.

Normal ergonomic issues like this are probably the cause. Can you get hold of an older model phone and relax with it for a few weeks to check whether the problems are really with the new devices?

Hmm, it may be what you say. Makes sense.

What I have done now is covered the notch with a tape and the strain is gone. Maybe it is that I got used to it as you suggest.

At some point I will remove the tape and see if the strain comes back or not.

You could try for a week with a little piece of electrical tape covering the IR light part of the notch and see if it improves. It shouldn’t leave any residue.

I believe there is a setting to toggle attention-tracking features, which tell the phone not to dim the display or lock itself when you’re looking at it. If you disable it I think this should stop, and along with disabling Face ID it should turn off the IR light altogether.

I used my 6s plus at night in bed for extended periods of time without eye soreness. Switched to the XS Max last month and my eyes have been sore every morning. Could you try taping the IR emitter and see if that helps?

Put some electrical/duct tape over it and give it a try. I'm interested in what you'll find.


Here's an epileptic claiming iPhone X triggered a seizure https://discussions.apple.com/thread/8291119

Many people on reddit claim to have had headaches from their phones, though some are convinced it is related to the display https://www.reddit.com/r/iPhoneX/comments/91krbq/headache/

Some have suggested covering the notch, as another test you could try watching your movie with the notch un-covered but with your room lights up a bit - so you reduce contrast from bright screen to dark background and let your pupils close somewhat.

My eyes have been feeling weird lately too. You really have me concerned about FaceID now.

I'd turn it off. Our eyes are not meant for IR flashes.


From your link: "Infrared light may cause damage to eyes in very intense concentrations, but it is highly unlikely that this would occur in everyday life. If you are working in close proximity to infrared lasers, wear the appropriate safety glasses or take appropriate protection measures."

The tiny LED on the front of the iPhone is nowhere near what you'd expect from industrial infrared lasers. I'm not sure the article makes the case that the infrared light from tiny LEDs is harmful.

This is with FaceID turned off!

Is it the same when turned on?

Yes. Just discovered, turning the “attention aware features” turns it off.


Interesting question. The same technology (IR laser projector) is used inside Microsoft's kinect (except they use a stronger projector), and people play that for extended periods of time, so definitely not the first consumer electronic to use this type of technology.

There are so many different things that can give you headaches (diet, hydration, sleep, stress, neurological issues, etc), it can be challenging to pin this down. I'd say it's more likely something else. Additionally, I find I get headaches from staring at tiny screens too long in general. I hope you feel better soon!

You're not looking directly into the Kinect though, you're usually looking at the screen which is a few inches/feet away from the Kinect.

I was initially skeptical, but your video made me change my mind. Why the hell is the flood illuminator going off when you're just looking at the Control Center?

I was thinking that too, shouldn't it only be used to unlock Face ID

I don't think it's a good idea to watch movies in an iphone in the dark. Your eyes weren't build to focus in a small screen full of light in a dark room. There's nothing good coming out of it.

True, but it makes me wonder why I never had problems with 3GS, 4, 6, 7+ and 8+. Only when I got the X last year I started having the symptoms.

Hey mate, your video is coming up as 'unavailable' for me, interested to see it however.

sfilargi - did you remove the video or was it taken down? Says "Video Unavailable" now

Everyone is exposed to an extremely powerful nuclear fusion IR flood illuminator every day, it's called the Sun. I doubt the tiny IR LED in your iPhone would cause any issues.

The difference is that when you are outside in the sun, there is visible light too, which means your pupils are about 2mm.

When you are in a dark room, they can be up to 8-9mm. This means 15x more light allowed in.

I am not saying that the LED in the video will destroy your eyes, but I do wonder if the eye-pain induced by the iPhone X that I had the past year is because of that.

And you have been trained not to look at it. Haven't you?

Infrared is light, and light is reflected. You don’t need to look directly at the sun to get get it in your eyes.

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact